1. Field of the Invention
The present invention relates to electronic displays, and methods of operating and manufacturing electronic displays.
2. Description of the Related Art
Electronic displays for displaying images are typically designed as regular arrays of light sources called picture elements, or “pixels.” Each pixel emits light to reproduce a small piece of the image being displayed. For color displays, each color pixel typically includes more than one light emitter, called “sub-pixels.” The color pixels usually include at least one red, one blue, and one green sub-pixel.
An electronic display signal includes the information needed for creating the image on the display. The display signal includes information corresponding to each pixel. The signal received by the pixel includes values corresponding to an amplitude of light for each of the corresponding one or more sub-pixels to generate. When a pixel includes multiple sub-pixels of different colors, the relative amplitudes of the sub-pixels determine the displayed color that is perceived by a viewer. The precise arrangement of sub-pixels, such as blue, red, and green sub-pixels, is not visible at appropriate viewing distances.
Pixels in a display are typically arranged in an array of rows and columns. Conventional pixel arrays have rows and columns of pixels arranged at right angles, also known as an “orthogonal” pixel array. FIG. 1 shows an orthogonal pixel array 100, with pixels 150 arranged in orthogonal rows 111 and columns 112. While, for purposes of explanation, the pixel display 100 shows only six rows and six columns of pixels, it should be understood that a typical orthogonal pixel array may include hundreds or thousands of rows and columns.
Types of light emitters used in pixels known in the art include light-emitting-diodes (LED's). For example, the sub-pixels of one type of LED pixel may include one red, one green, and one blue LED. Other commonly known types of light emitters used in pixels include plasma, liquid crystal display (LCD), and cathode ray tube (for small displays), to name but a few.
Pixel arrays having LED pixels may be constructed using either “through-hole” or “surface-mount” type devices, as are known in the art. Through-hole devices, on the one hand, include discrete LED sub-pixels or discrete LED pixels which are mounted individually on a circuit board by fitting wire leads of the discrete elements into holes in the circuit board. Surface-mount devices, on the other hand, are mounted directly onto the surface of, and electrically connected to, a circuit board having wiring already printed on its surface to correspond to the wiring of the surface-mount devices.
Pixel array 100 and their associated circuit boards, if any, may be divided into sub-arrays each supported by a respective one of modules 12a-c, 14a-c and 16a-c. Each module may provide its respective sub-array of pixels with a supporting mechanical frame (not shown) and individual electronic control. Thus, dividing the pixels into modules may provide the advantages of improving the mechanical integrity and modularity of the electronic display such that the display is easier to build and maintain. For ease of illustration, each of modules 12a-c, 14a-c and 16a-c is shown as supporting a sub-array of only two rows and two columns of pixels. However, it is to be understood that each module may support tens or hundreds of rows and columns. Similarly, for ease of illustration, only three rows and three columns of modules are shown. However, it should be understood that a typical electronic display may include tens or hundreds of rows and columns of modules.
As shown in the electronic display arrangement 10 of FIG. 2, the modules in each row of modules may be connected sequentially in series to a sign controller 18. Sign controller 18 may provide display data (e.g., specify whether each lighting element should be ON or OFF, and specify the color and brightness of each lighting element when ON) to each module through the series connections. That is, the display data flows from left to right from sign controller 18 to each of modules 12a-c in sequence; from sign controller 18 to each of modules 14a-c in sequence; and from sign controller 18 to each of modules 16a-c in sequence. A problem, however, is that if one of the modules malfunctions, then the malfunctioning module may be unable to pass data to the other modules that are downstream from the malfunctioning module. For example, if module 12a malfunctions, then modules 12b-c may not receive their display data, and the entire row of modules may not display properly. With long series connections, it may be particularly visually noticeable if a large number of horizontally adjacent modules are not displaying properly.
What is neither disclosed nor suggested in the conventional art is an electronic display in which the failure of one module does not affect the performance of other modules in the display.